How to inherit from RadTextBox?

[Zdeněk]

I want to extend RadTextBox by implementing RequiredFieldValidator. I did simillar functionality with asp:textbox :

Public Class MyTextBox
        Inherits WebControls.TextBox

        Private req As New RequiredFieldValidator

        Protected Overrides Sub OnInit(ByVal e As EventArgs)
            req.ControlToValidate = Me.ID
            req.Display = ValidatorDisplay.Dynamic
            req.ErrorMessage = "Please fill marked field(-s)"
            req.Text = "*"
            req.EnableClientScript = True
            Controls.Add(req)
        End Sub

        Protected Overrides Sub Render(ByVal w As HtmlTextWriter)
            MyBase.Render(w)
            req.RenderControl(w)
        End Sub

 End Class

When I want to inherit from RadTextBox (at line 2: Inherits Telerik.Web.UI.RadTextBox), code stops working with weird error:

Unable to find control id 'txtTest' referenced by the 'ControlToValidate' property of ''.

What I'm doing wrong? Thank you for your help!

Zdenek

[Pavel]

Hi Zdenek,

I am afraid that inheriting from RadTextBox in that way is not supported due to limitation that prevents the Validator from getting the correct ID. You can try inheriting from WebControl instead and putting the RadTextbox and its validator inside it.

Best wishes,
Pavel
the Telerik team

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[Zdeněk]

Thank you. Most needed functionality will bring me RadInputManager.